1. Field of the Invention
The present invention relates generally to Global Positioning System (GPS) receivers, and in particular, to a GPS receiver with a configurable search engine.
2. Description of the Related Art
The use of GPS in consumer products has become commonplace. Hand-held devices used for mountaineering, automobile navigation systems, and GPS for use with cellular telephones are just a few examples of consumer products using GPS technology.
GPS-enabled devices, such as cellular telephones, have also been introduced into the consumer marketplace. These devices allow for the use of Location-Based Services (LBS) which are services, advertisements, and other features that are offered based on the location of the user. As such, GPS-enabled devices are used worldwide.
One of the most pressing problems with GPS devices is that it takes a certain amount of time to initially acquire satellites, and, when the satellite signals are lost, that it is sometimes difficult and time consuming to find the satellite signals again. The search engine of the GPS receiver, typically a correlator, compares a block of known code against the signal and looks for a correlation between the received signal and the known code, and does this search over a given frequency range and a given time. However, little or no intelligence about the prior signals is used to shorten the time to find satellites a second or subsequent time.
It can be seen, then, that there is a need in the art to make GPS-enabled devices that shorten the reacquisition time for satellites in a GPS device-based system.